| 摘要 |
Cellulose sulfate esters are cross-linked with tetravalent metal ions at a threshold pH of about 3.0 or higher. The cross-linked products have a higher aqueous viscosity and are more highly pseudoplastic than the precursor cellulose sulfate and may also exhibit a relatively high yield point. The products may be employed in forming thickened aqueous compositions and cohesive gel-like compositions. The presence of other metallic ions, in addition to the tetravalent metal ions, is beneficial and enhances the viscosity increase produced by cross-linking of the cellulose sulfate with the tetravalent metal ions. The invention is directed to a process for cross-linking of cellulose sulfate esters with tetravalent metal ions, to mixtures of cellulose sulfate esters and tetravalent metal ions that may be used in producing cross-linking of the cellulose sulfate, to a cellulose sulfate product which is cross-linked with tetravalent metal ions, and to aqueous compositions containing cellulose sulfate cross-linked with tetravalent metal ions.
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